Electric garage door openers have become very commonplace. A reversible motor is normally mounted on a garage ceiling. The garage door, mounted to move along tracks from a fully open position to a fully closed position, is connected to the reversible motor. A remote controller which is usually kept in the auto is used to open and close the door. A door switch is also normally mounted inside the garage near the garage door frame and hard-wired to the reversible motor. As well known, the common electric door opener is a real convenience to the car owner. It also eliminates back strain oftentimes experienced by having to manually open a garage door.
In recent years, electric garage door opener systems have been required to include safety devices to prevent the door from accidently closing on an individual or object. For example, an infrared transmitter unit and a receiver unit are mounted on the garage door's frame usually near ground surface and usually inside the garage. The transmitter emits a light beam directly across to the receiver. As long as the light beam is uninterrupted, it is presumed no object is in the travel path of the garage door. If the light beam is interrupted by the presence of an object, a signal is sent to the reversible motor to stop further movement of the garage door. The transmitter and receiver are laterally offset a few inches from the garage door. Also, they sense only objects which extend fully or almost fully to the ground surface. In most cases, this is adequate. However, it is possible with this type of detecting system for an object to be located such that it will not be detected by the sensors, yet still be in the travel path of the garage door. For example, an auto may be only partially pulled into the garage such that its wheels are not in the light beam of the infrared ray transmission, yet its trunk lid extends outwardly and is in the garage door's travel path. A closing garage door will hit the trunk lid with sufficient force that noticeable damage occurs.
The ultimate object sensor for an electric garage door opener would sense objects directly in the path of the garage door's leading edge to eliminate "blind spots" associated with present garage door opener systems. The object sensor would also respond promptly to the presence of an object and stop further garage door movement. In accord with this need, there has now been developed a garage door mountable object sensor system which moves with the door to sense objects directly in the path of the door's leading edge. The sensor system is readily mounted on the garage door and either hard-wired to the opener's reversible motor or is battery operated. Most importantly, the object sensor is mounted in a manner which allows the garage door to open and close as normal.